RATS have a lot more in common with humans than you may think! Scientists have just mapped out the entire chemical makeup of the common rat.

The rat is just the third animal to have its genes mapped out. The other two are humans and mice.

Genes are tiny sets of chemical instructions that determine how each living creature looks and behaves. They also help determine why we get sick from certain diseases.

This new research will help scientists fight illnesses by identifying disease-related genes. It will also advance medical research into how genes and the environment affect our health. The research was reported in the Nature magazine.

Why do scientists study rats?

Rats are often used by scientists to learn more about diseases and medicine.

What's so special about rats? This new research shows that a Norway rat has more than 25,000 genes and about 90 percent of those genes are just like the ones you'd find in mice and people! Scientists believe all three species shared a common ancestor about 75 million years ago.

There are some major differences among the three animals. For example, the rat relies more heavily on its sense of smell than a human. It also has more genes devoted to smelling and identifying scents.

One of the more surprising findings is how fast genes changed, over time. Scientists believe that this may mean that rats are more easily able to adapt to their environment.

Said Howard Jacob of the Medical College of Wisconsin, the co-author of the study: This discovery "is simply a revolution in the way we can practice basic research."

Fast fact

There are about 50,000 genes we inherit from our parents that make us look the way we do.

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